\usetikzlibrary{shadows}
\usetikzlibrary{arrows}
\begin{tikzpicture}

\node [shape=circle, minimum size=0.5cm, very thick, draw=black] (v0) at (-5,1) {};
\node [ shape=circle, minimum size=0.5cm, very thick, draw=black] (v1) at (1,1) {};
\node [ shape=circle, minimum size=0.5cm, very thick, draw=black] (v2) at (7,1) {};
\draw [very thick, bend right] (v0) edge (v1);
\draw [ very thick, bend left] (v0) edge (v1);
\draw [ very thick] (v1) edge (v2);
\node at (-5,1) {\Large $s$};
\node at (7,1) {\Large $t$};
\node at (-2,2.3) {\Large $1$};
\node at (3.8,1.3) {\Large $1$};
\node at (-2,-0.3) {\Large $1$};

\end{tikzpicture}